(The Big Bang is the expansion of the universe
from an incredibly hot dense beginning
about 15 billion years ago.)

These were formed from a hot "soup" of protons and neutrons.
when the universe was only 3 minutes old.

DENSITY OF NEUTRONS AND PROTONS in the universe determined the
abundances of certain elements. For a
higher-density universe, the computed helium abundance is little different, and the
computed abundance of deuterium is
considerably lower. The shaded region is consistent with the observations, ranging from an
abundance of 24 percent for helium
to one part in 1010 for the lithium isotope. This quantitative agreement of theory and
observation is a prime success of the big
bang cosmology.

Accelerators have reproduced the conditions in the Big Bang
when the universe was only 0.00001 second old (one ten-millionth of a second)!

a quark-gluon plasma

Our understanding of how the universe was created, which was previously
unverified theory for any point in time before the formation of ordinary atomic nuclei,
about three minutes after the Big Bang, has with these results now been experimentally
tested back to a point only a few microseconds after the Big Bang.